Lots of interesting reviews on here for Kind Words. I'd like to add that I find its core "gameplay" design to be very wise. When someone posts a "Request" message, other people can each reply once to that, and that's it. There's no inbuilt way to go back and forth. Yes, you could insert personal information, but that's not encouraged. The anonymity is the point.

This addresses the problems of expertise, dependency, and toxicity.

Expertise, as most people aren't qualified mental health professionals. The character limit also puts brakes on how much is discussed.

Dependency, as sustained correspondence between a suffering person and a (presumed) good Samaritan could be detrimental to either party.

Toxicity, as Kind Words is trying to raise positive energy from the masses on Steam. You know how savage the gaming community can be at times. Anyone who receives an uncivil message in-game can report it.